Liquid-cooled cylinder head for internal combustion engines



Sheet of 2 R. SEIFERT Jan. 7, 1969 LIQUIDCOQLED CYLINDER HEAD FOR INTERNAL COMBUSTION ENGINES Filed Nov. 29, 1966 Jan. 7, 1969 R. SEIFERT 3,420,215

LIQUIDCO0LED CYLINDER HEAD FOR INTERNAL COMBUSTION ENGINES Filed Nov. 29. 1966 Sheet 2 of 2 INVENTOR Rum/920 SE1 FGRT ATTORNEYS United States Patent 3,420,215 LIQUID-COOLED CYLINDER HEAD FOR INTERNAL COMBUSTION ENGINES Richard Seifert, Friedrichshafen-Manzell, Germany, assignor to Maybach Mercedes-Benz Motorenbau G.m.b.H., Friedrichschafen, Germany Filed Nov. 29, 1966, Ser. No. 597,593 Claims priority, application Germany, Dec. 10, 1965,

US. Cl. 12332 Claims Int. Cl. F01p 3/12; F01p 3/14; F0213 1/36 ABSTRACT OF THE DISCLOSURE A liquid-cooled cast cylinder head for an air-compressing internal combustion engine with multiple overhead valves, the fuel being injected into a pre-combustion chamber arranged in the cylinder-axial direction, intermediate bottom wall means extending from the outer walls to the inlet and exhaust ports, cylindrical support walls provided with apertures for cooling water passage arranged between the bottom wall and the intermediate bottom wall, a basket-like hollow body acting as support between the bottom and top wall and surrounding the precombustion chamber within a predetermined distance, apertures for the cooling medium uniformly distributed over the circumference of the hollow body, and the hollow body being cylindrically shaped above and conically below the intermediate bottom wall.

Background and summary of the invention The present invention relates to a liquid-cooled, castiron cylinder head for an air-compressing internal combustion engine with high specific output and with compression-ignition of the fuel injected into a cylinder axially arranged pre-combustion chamber, and provided with several, preferably four or six, overhead valves. The cylinder head includes an intermediate bottom wall extending from the outer walls of the cylinder head to the valve ports. Furthermore, the cylinder head is provided with an approximately cylindrical supporting wall be tween the bottom wall and the intermediate bottom wall which is adjoined by the bosses for the cylinder head bolts. The supporting wall transmits the thrust and pressure of these bolts to a cylinder liner gasket. The ports or apertures for the cooling liquid entering from the cylinder housing are located in the bottom wall outside of the supporting wall, and more particularly on the inlet side as also on the exhaust side, especially several ports or apertures being provided on the exhaust side. Apertures are provided in the supporting wall for the passage of the cooling liquid which continues to flow toward the center (FIGURE 1 of the drawing herein as, for example, also previously published in the journal Schiff und Hafen (Ship and Harbor), volume 7 (1955), Number 7 (July); in the part of the article by PULS entitled The Maybach Main Propulsion and Auxiliary Engines of the seaside resort passenger ship Wappen von Hamburg, page 426 fli, FIGURES 55 and 61; and German Patents 832, 703 and 849, 780).

In this construction of the prior art, the pre-COmbustion chamber is included in the cylinder head casting, i.e., is case integrally therewith. The burner is screwed into the mouth of the pre-combustion chamber. It is already possible by this type of construction to construct the bottom wall of the cylinder head very thin. However, due to the extremely high thermal and also mechanical stresses caused by the ignition pressure, the combustion chamber may become damaged, especially in case of Patented Jan. 7, 1969 faulty castings so that the entire cylinder head then has to be replaced,

Consequently, according to the present invention, the following features are combined in order to avoid the disadvantages of the prior art type of design and construction:

(a) The cylinder head includes a basket-like hollow body as support between the bottom and top wall of the cylinder head which hollow body is arranged cylinderaxially at a certain distance both from the valve ports and the valve guides as well as also from the pre-colmbustion chamber, installed and inserted in a known manner, the lower part of this hollow body which faces the bottom wall forming a collar for the mounting and fastening of the pre-combustion chamber, especially of the burner thereof;

(b) The intermediate bottom wall extends beyond the valve ports up to the basket-like hollow body surrounding the pre-combustion chamber;

(c) The ports or apertures of the basket-like hollow body surrounding the pre-combustion chamber are arranged below and above the intermediate bottom wall.

The basket-like hollow body, to be referred to hereinafter as pre-combustion chamber basket, surrounding the pre-oornbustion chamber, about which flows the cooling liquid on the inside and outside thereof, serves only as support and is, therefore, only exposed to the mechanical loads and stresses especially from the ignition pressures, in the absorption of which partakes the reinforcing, barrel-hoop-like eltect of the intermediate bottom wall extending all the way to the pre-combustion chamber basket. The inserted and therewith easily replaceable pre-combustion chamber is exposed to the mechanical stresses originating from the ignition pressure as well as to the high thermal stresses of the pre-combustion. The pre-combustion chamber advantageously is made from a heat-resistant material of high strength. The pre-combustion chamber can be welded together with the burner made of high-heat-resistant material, and may be screwed into the pre-combustion chamber basket provided with a collar.

One type of construction of the prior art is already provided with a hollow body surrounding the inserted pre-combustion chamber. However, this prior art hollow body closely adjoins and embraces the precombustion chamber between hte valve guides. Only along the valve guides, port holes are provided in this prior art hollow body for the cooling liquid flowing from a lower into an upper ringshaped chamber. Owing to this close connection of this prior art hollow body with the valve guides, the heat is transferred to the latter and thereby gives rise to troubles at the valve stems. In addition thereto, the prior art cylinder head has an extremely thick bottom wall (US. Patent 2,619,078). In contradistinction thereto, one of the characteristics of the present invention is that the basket-like hollow body is arranged at a certain distance from both the valve ports as also from the important lower portion of the valve guides. Of special importance is the spacing between the pre-combustion chamber basket and the pr-e-combustion chamber since in that case the pre-combustion chamber is circumcirculated unobstructedly by the cooling liquid. The valve guides, in particularly, the ones on the exhaust side therefore cannot receive any direct heat supply from the pre-combustion chamber but are only warmed-up insignificantly by the cooling liquid itself.

In another prior art embodiment of a cylinder head, the inserted precombustion chamber is closely surrounded by a thrust sleeve provided with openings. The cooling liquid can reach the pre-combustion chamber in this prior art construction only at the places of openings or apertures so that, owing to the narrow space and contact, the thrust sleeve is thermally highly stressed and only cooled from one side. Additionally, the thrust sleeve is inserted in the same way as the pre-combustion chamber thereby requiring an extensive and costly constructional expenditure for its fitting (German Patent 546,869). The flanges and mounting bolts required and provided for the fitting make it impossible therefore to construct the cylinder head bottom wall relatively thin as can be achieved by the present invention.

According to one embodiment of the present invention, generally the ports or apertures for the cooling liquid are regularly arranged or uniformly distributed about the circumference of the pre-combustion chamber basket. If the valves are arranged on the same diameter and with the same spacings between one another, the equal distribution of the ports for the cooling liquid on the pre-combustion chamber basket is obtained automatically. Advantageously, the ports are arranged in approximately the same radial directions as the valves. This offers the advantage that the cooling liquid coming from the space between the intermediate bottom wall and the bottom wall and flowing about the valve ports, enters uniformly behind the valve ports through the openings or apertures provided in the lower section of the hollow body, flows upwardly along the combustion chamber in counter-current relation with respect to the temperature gradient increasing in the downward direction owing to the combustion, and leaves the space between the pro-chamber and the pre-combustion chamber basket over the entire circumference thereof in the direction of the valve guides, thus achieving intensive cooling of both the pre-combustion chamber and pre-combustion chamber basket.

According to a particularly preferred embodiment of the present invention, the part of the pre-combustion chamber basket above the intermediate bottom wall is cylindrically shaped and changes over below the intermediate bottom wall into a tapered, conical part, chamfering towards the bottom wall, from which is flanged the collar accommodating the burner. This shape and form is favorable for the circulation of the cooling liquid which, as a result thereof, is faster at the lower and hottest conical part and slower along the cylindrical portion of the pre-combustion chamber basket.

In internal combustion engines having less than six valves, in which the spaces between the valve ports and the valve guides may be wider than in engines, for example, with six valves, the circulation of the cooling liquid is improved and regulated by the arrangement of guide ribs located radially between the valve ports (German Patent 389,290 and US. Patent 1,479,129).

These guide ribs advantageously extend between the inlet and exhaust sides up to the top wall and, together with the surrounding wall parts, adjoin the neighboring bosses for the cylinder head bolts. A good strengthening and sufiicient reinforcement of the cylinder head is achieved thereby at these places. This strengthening and reinforcement is already present at the inlet and exhaust sides owing to the gas ports or channels.

In case of V-shaped engines, the space between the intermediate bottom wall and the bottom wall is inclined corresponding to the V-angle. In order to avoid the formation of air or stream bubbles at the highest spots of the intermediate bottom wall which may cause heat accumulations, ports are arranged advantageously at these spots. These ports or apertures entail the further advantage that a gas port which may be arranged at this place, especially an exhaust gas port, is swept over by a cooler branch flow of the cooling liquid which branches otf already below the intermediate bottom wall and therefore is not heated up already by the pre-combustion chamber.

Accordingly, it is an object of the present invention to provide a liquid-cooled cylinder head for internal combustion engines which obviates by extremely simple and inexpensive means the drawbacks and shortcomings encountered with the prior art constructions.

Another object of the present invention resides in a liquid-cooled cylinder head for internal combustion engines which not only can be provided with a relatively thin bottom wall but which does not require an exchange of the entire cylinder head in case of failures or defects in the combustion chamber.

A further object of the present invention resides in a liquid-cooled cylinder head for internal combustion engines in which the combustion chamber is constituted by a separate, detachable insert member made of suitable heat-resistant material which can be readily installed into the cylinder head.

Still another object of the present invention resides in a liquid-cooled cylinder head for internal combustion engines provided with a pre-combustion chamber basket which is cooled both on the inside and outside thereof and is exposed essentially only to mechanical stresses stemming from ignition pressures.

A still further object of the present invention resides in a liquid-cooled cylinder head for internal combustion engines in which the pre-chamber can be readily interchanged.

Still another object of the present invention resides in a liquid-cooled cylinder head having an improved cooling system to avoid over-heating of the valve guides and prevent troubles at the valve stems.

A further object of the present invention resides in a cylinder head for a liquid-cooled internal combustion engine which is relatively simple in construction and design, inexpensive in manufacture, permits the use of relatively thin walls without impairment to the rigidity and assures completely satisfactory cooling of all the parts.

A still further object of the present invention resides in a liquid-cooled cylinder head for internal combustion engines in which the burner is effectively cooled in an appropriate manner taking into consideraiton the heat gradient thereof.

Brief description of the drawing These and further objects, features, and advantages of the present invention will become more obvious from the following description when taken in connection with the accompanying drawing which shows, for purposes of illustration only, several embodiments in accordance with the present invention, and wherein:

FIGURE 1 is a transverse cross-sectional view through a prior art liquid-cooled cylinder head for an internal combustion engine with six overhead valves;

FIGURE 2 is a transverse cross-sectional view, similar to FIGURE 1, through a liquid-cooled cylinder head in accordance with the present invention for an internal combustion engine also provided with six overhead valves;

FIGURE 3 is a partial transverse cross-sectional view, similar to FIGURE 2, with the pre-chamber removed for sake of clarity;

FIGURES 4 and 5 are partial cross-sectional views, taken along lines 4-4 and 5--5 of FIGURE 3;

FIGURE 6 is a partial transverse cross-sectional view, similar to FIGURE 3, of a modified embodiment of a liquid-cooled cylinder head in accordance with the present invention for an internal combustion engine with four overhead valves; and

FIGURES 7 and 8 are partial cross-sectional views, taken along line 77 and 8-8 respectively, of FIG- URE 6.

Detailed description of the drawing Referring now to the various views of the drawing wherein like reference numerals are used throughout the various views, FIGURES 1 to 3 and 6 illustrate cross-sectional views of the cylinder head, transverse to the engine axis, while FIGURES 4, 5, 7 and 8 are cross-sectional views taken at right angle to the transverse cross sections of FIGURES 1 to 3 and 6 along the lines indicated in FIGURES 3 and 6, respectively.

FIGURES 3 to 5 and FIGURES 7 and 8, respectively, illustrate the exhaust side of the cylinder head which, with V-shaped engines, is positioned toward the engine saddle.

Referring now more particularly to FIGURES 1 and 2, reference numeral 1 designates therein a conventional injector unit, reference numeral 2 a control cam, reference numeral 3 the valve spring for an inlet valve 4, and reference numeral 5 the valve spring for an exhaust valve 6. The valve plates or valve disks are not shown in FIGURE 2 for the sake of clarity. Furthermore, in both FIGURES l and 2, the cylinder housing is designated by reference numeral 7, the cylinder liner by reference numeral 8, and the gasket for the cylinder liner by reference numeral 9. The ports 10 for the cooling water in the cylinder housing 8 are located at the inlet side while the cooling water ports 11 are located on the exhaust side, the respective gaskets for these ports being designated by reference numerals 12 and 13.

According to FIGURE 1, a pre-cornbustion chamber 14 is cast-in in a cylinder-axial direction; a burner 15 with burner holes 16 is screwed into the mouth of the pre-chamber 14.

According to the embodiment of FIGURE 2, a precombustion chamber 17, made of heat-resistant material is inserted cylinder-axially or coaxially to the cylinder into the cylinder head. A burner 18 of special high-heatresistant material is welded to the pre-combustion chamber 17, thereby forming one piece with the pro-combustion chamber 17.

The cylinder head shown in FIGURE 1 is provided with an intermediate bottom wall 19 extending from the outer walls 20 and 21 to the valve ports 22 and 23. Furthermore, the cylinder head includes a cylindrical supporting wall 24, located between the bottom Wall 25 and the intermediate bottom wall 19. This supporting wall 24 transmits the thrust of the cylinder head bolts onto the cylinder liner gasket 9. The ports 10 and 11 for the cooling liquid leaving the cylinder housing 7 and entering the cylinder head are located in the bottom wall 25, outside of the supporting wall 24. Apertures are provided in the supporting wall 24 for the passage of the cooling liquid which continues to flow toward the center in the direction toward the pre-combustion chamber 14.

The cylinder head according to FIGURES 2 to 5 is provided with a basket-type hollow body generally designated by reference numeral 27 acting as support between the bottom wall 28 and the top Wall 29, and cylinderaxially arranged at a certain distance not only from the valve ports 30, 31 and the valve guides 32, 33 but also from the pre-combustion chamber 17.

For the purpose of screwing-in the pre-combustion chamber 17, and especially of its burner 18, the pre-combustion chamber basket 27 is provided with a collar 34. The intermediate bottom wall, which in the cylinder head according to FIGURE 1 extends as bottom wall 19 only up to the valve ports, extends in the embodiment of FIG- URE 2 according to the present invention beyond the valve ports 30, 31 as indicated by the dash lines and designated by reference numeral 35, up to the Wall 36 of the basket 27 surrounding the pre-combustion chamber. Be low the intermediate bottom wall 35, the pre-combustion chamber basket 27 is provided with ports or apertures 37 for the inlet of the cooling liquid, and above the intermediate bottom wall 35 with ports or apertures 38 for the outlet of the cooling liquid.

Generally, the cooling liquid ports 37, 38, provided in the pre-combusti0n chamber basket 27, are uniformly distributed over its circumference, provided the valves 4 and 6 are arranged at the same distances to each other and on the same diameters. In this case, the ports are arranged in the same radial directions as the valves.

Above the intermediate bottom wall 35, the pre-combustion chamber basket 27 is shaped cylindrically and passes over below the intermediate bottom wall into a conical, tapered part from which is flanged the collar 34 accommodating the burner 18.

Similar to the cylinder head according to FIGURE 1, the cylinder head according to FIGURES 2 to 5 is also provided with a cylindrical supporting wall 39 having ports or apertures 40 for the flow of the cooling liquid. As can be seen particularly clearly from FIGURES 4 and 5, bosses 41 for the cylinder head bolts adjoin this supporting wall 39. The cooling water entering through the ports 10 and 11 flows through the ports 40 around the valve ports 30, 31 toward the center and enters the precombustion chamber basket 27 by way of the ports 37, flows along the pre-combustion chamber 17 in the upward direction, leaves the pro-combustion chamber 27 in a radial direction while flowing around the valve guides 32, 33 and leaves the cylinder head through one or several outlet ports 42.

The cylinder head according to FIGURES 6 to 8 for an engine with four valves is constructed in a similar manner. In FIGURES 6 to 8, reference numeral 43 designates the pre-combustion chamber basket, reference numeral 44 the bottom wall, reference numeral 45 the top wall, reference numeral 46 the valve ports, reference numeral 47 the valve guides, reference numeral 48 the collar of the pre-combustion chamber basket 43, reference numeral 49 the intermediate bottom wall which extends all the way to the outer wall 50 of the pre-combustion chamber basket 43, reference numeral 51 the inlet ports, reference numeral 52 the outlet ports of the pre-combustion basket 43, reference numeral 53 the cylindrical supporting wall, reference numeral 54 the cooling liquid ports in the cylindrical supporting wall 53 and reference numeral 55 the bosses for the cylinder head bolts which adjoin the cylindrical supporting wall 53.

Ribs 56 are disposed between the valve ports 46. As can be seen from FIGURE 6, the ribs 56 extend all the way to the top wall 45 and adjoin with the wall parts 57 thereof at the adjacent bosses 55 for the cylinder head bolts. A vent hole 58 (FIG. 7) is arranged at the highest spots of the intermediate bottom wall 49, which results from the inclined position in V-engines. The air and steam bubbles forming at such spots are taken along by the cooling liquid. Additionally, the vent hole 58 as illustrated at the valve port 46 has the special advantage that already at this location cooling liquid can branch off in by-pass relationship with respect to the main flow of the cooling liquid and cools effectively the exhaust port.

While I have shown and described two embodiments in accordance with the present invention, it is understood that the same is not limited thereto but is susceptible of numerous changes and modifications as known to a person skilled in the art, and I therefore do not wish to be limited to the details shown and described herein, but intend to cover all such changes and modifications as are encompassed by the scope of the appended claims.

I claim:

1. A liquid-cooled cast cylinder head for an air-compressing internal combustion engine with high specific output and compression-ignition of the fuel injected into a pre-combustion chamber extending approximately in the axial direction of the cylinder, comprising means in said cylinder head for accommodating a plurality of overhead valves including valve port means and valve guide means, intermediate bottom Wall means extending substantially from the outer walls of the cylinder head to the valve port means, bottom and top wall means, approximately cylindrical supporting wall means between the bottom wall means and the intermediate bottom wall means, boss means for the cylinder bolts adjoining said supporting wall means, said bottom wall means being provided with inlet aperture means for the cooling liquid outside of said supporting Wall means on the inlet and exhaust side, said supporting wall means being provided with aperture means for the passage of the cooling liquid toward the center, basket-like hollow body means as support between the bottom wall and top wall means, pre-combustion chamber means inserted into said hollow body means, said hollow body means having a predetermined distance from said valve port and valve guide means as well as from said pro-combustion chamber means, burner means secured to said pre-combustion chamber means, the lower portion of said hollow body means facing the bottom wall means being provided with a collar for accommodating said burner means, said intermediate bottom wall means extending beyond the valve port means up to the walls forming the hollow body means surrounding said precombustion chamber means, and said hollow body means being provided with aperture means below and above the intermediate bottom Wall means.

2. A cylinder head according to claim 1, wherein the aperture means for the cooling medium are distributed uniformly over the circumference at said basket-like hollow body means.

3. A cylinder head according to claim 2, wherein the cooling medium aperture means in said basket-like hollow body means are arranged approximately in the same radial direction as the engine valves.

4. A cylinder head according to claim 3, wherein said basket-like hollow body means is substantially cylindrical about the intermediate bottom wall means and passes over below the intermediate bottom wall means into a tapering conical portion flanged over into said collar.

5. A cylinder head according to claim 4, for internal combustion engines with four valves, further comprising rib means arranged between the valve port means.

6. A cylinder head according to claim 5, wherein the rib means extend between the inlet and exhaust side up to the top wall means and adjoin with wall parts thereof the cylinder bolt boss means.

7. A cylinder head according to claim 6, for V-engines, wherein aperture means are provided substantially at the highest places of the intermediate bottom wall means.

8. A cylinder head according to claim 1, wherein the cooling medium aperture means in said basket-like hollow body means are arranged approximately in the same radial direction as the engine valves.

9. A cylinder head according to claim 8, wherein said basket-like hollow body means is substantially cylindrical above the intermediate bottom Wall means and passes over below the intermediate bottom wall means into a tapering conical portion flanged over into said collar.

10. A cylinder head according to claim 1, for internal combustion engines with four valves, further comprising rib means arranged between the valve port means.

11. A cylinder head according to claim 10, wherein the rib means extend between the inlet and exhaust side up to the top wall means and adjoin with wall parts thereof the cylinder bolt boss means.

- 12. A cylinder head according to claim 11, for V-engines, wherein aperture means are provided substantially at the highest places of the intermediate bottom wall means.

13. A cylinder head according to claim 10, for V-engines, wherein aperture means are provided substantially at the highest places of the intermediate bottom wall means.

14. A cylinder head according to claim 1, wherein said basket-like hollow body means is substantially cylindrical above the intermediate bottom wall means and passes over below the intermediate bottom Wall means into a tapering conical portion flanged over into said collar.

15. A cylinder head according to claim 14, wherein the aperture means for the cooling medium are distributed uniformly over the circumference at said basket-like hollow body means.

References Cited UNITED STATES PATENTS 1,479,129 1/1924 Feilner 12341.76 2,619,078 11/1952 Witzky et a1. 12332 2,710,602 6/1955 Maybach 12341.76 2,739,579 3/1956 Ware 12341.31 2,778,347 1/ 1957 Von Mallinckrodt 12332 2,788,776 4/1957 Holt 12341.82 3,025,839 3/1962 Crowther et a1 12332 3,081,755 3/1963 Kotlin et a1 12341.77 3,176,666 4/ 1965 Whitehead l23-4l.82 3,315,652 4/1967 Ries et al 12341.31

FOREIGN PATENTS 849,780 9/ 1952 Germany. 744,554 2/ 1956 Great Britain.

AL LAWRENCE SMITH, Primary Examiner.

US. Cl. X.R. 

